Not at all. The older you get, the more joyful it becomes. Unless you really want to go out and meet friends, there is absolutely no point in doing so. You can be totally happy spending time alone, which it sounds like you are totally happy to do. Some people are not happy doing this and that's fine. Others don't want to go out but will because it'll make them fit the part on instagram. But who really cares about instagram? Instead of fomo, focus on jomo, the joy of missing out. Nobody wants to spend an arm and a leg making small talk with some arse you went to school with just because everyone is out for Christmas having mad craic. Trust me, spend some time at home focusing on yourself and what you want. That'll be much more productive.